Unconsciousness is a state in which a living
individual exhibits a complete, or near-complete, inability to maintain an
awareness of self and environment or to respond to any human or environmental
stimulus.
Unconsciousness may occur as the result of
traumatic brain injury,
brain hypoxia (inadequate oxygen, possibly due to a brain
infarction or
cardiac arrest), severe intoxication with drugs that
depress the activity of the central nervous system (e.g.,
alcohol and other
hypnotic or
sedative drugs), severe
fatigue,
pain,
anaesthesia, and other causes.
Loss of consciousness should not be confused with the notion of the
psychoanalytic unconscious, cognitive processes that take place outside awareness (e.g.,
implicit cognition), and with
altered states of consciousness such as
sleep,
delirium,
hypnosis
Hypnosis is a human condition involving focused attention (the selective attention/selective inattention hypothesis, SASI), reduced peripheral awareness, and an enhanced capacity to respond to suggestion.In 2015, the American Psychologica ...
, and other altered states in which the person responds to stimuli, including
trance
Trance is a state of semi-consciousness in which a person is not self-aware and is either altogether unresponsive to external stimuli (but nevertheless capable of pursuing and realizing an aim) or is selectively responsive in following the dir ...
and
psychedelic experiences.
Law and medicine
In
jurisprudence
Jurisprudence, or legal theory, is the theoretical study of the propriety of law. Scholars of jurisprudence seek to explain the nature of law in its most general form and they also seek to achieve a deeper understanding of legal reasoning ...
, unconsciousness may entitle the
criminal defendant to the
defense of
automatism, i.e. a state without control of one's own actions, an
excusing condition that allows a defendant to argue that they should not be held criminally
liable for their actions or
omissions. In most countries, courts must consider whether unconsciousness in a situation can be accepted as a defense; it can vary from case to case. Hence
epileptic seizure
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or neural oscillation, synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much o ...
s,
neurological dysfunctions and
sleepwalking may be considered acceptable excusing conditions because the loss of control is not foreseeable, but falling asleep (especially while driving or during any other safety-critical activity) may not, because natural sleep rarely overcomes an ordinary person without warning.
In many countries, it is presumed that someone who is less than fully conscious cannot give
consent to anything. This can be relevant in cases of
sexual assault
Sexual assault is an act in which one intentionally sexually touches another person without that person's consent, or coerces or physically forces a person to engage in a sexual act against their will. It is a form of sexual violence, whi ...
,
euthanasia, or patients giving
informed consent with regard to starting or stopping a medical treatment.
See also
*
Coma
*
Do not resuscitate
*
Greyout
*
Hypnosis
Hypnosis is a human condition involving focused attention (the selective attention/selective inattention hypothesis, SASI), reduced peripheral awareness, and an enhanced capacity to respond to suggestion.In 2015, the American Psychologica ...
*
Living will
*
Shallow water blackout
*
Sleep
*
Somnophilia
Somnophilia (from Latin ''somnus'' "sleep" and Greek φιλία, ''-philia'' "friendship") is a paraphilia in which an individual becomes sexually aroused by someone who is unconscious.Flora 2001, p. 92. ''The Dictionary of Psychology'' cate ...
*
Syncope (fainting)
*
Trance
Trance is a state of semi-consciousness in which a person is not self-aware and is either altogether unresponsive to external stimuli (but nevertheless capable of pursuing and realizing an aim) or is selectively responsive in following the dir ...
*
Traumatic brain injury
*
Twilight sleep
References
External links
{{Consciousness
Consciousness studies
Symptoms and signs of mental disorders